Recent advances in fish hatchery management

Abstract

The advancement of aquaculture has often been bottlenecked because of the lack of seed, but once that bottleneck was overcome there was rapid growth. Recent examples of advances in hatchery technology leading to increased production are sea bream and Pangasius. Three areas contributing to the advancement of hatchery management are: brood stock management, induced spawning and larval feeding. Formulated diets have been developed for marine brood fish that are equal or better than the traditional raw fish diets. The importance of lipids and their composition in brood fish diets, particularly n-3 HUFAs has received much attention. The lipid composition of the brood diet is reflected in egg composition and egg quality. Protein quantity and quality in brood diets also impacts reproductive success and egg quality. The use of Gonadotropin-releasing hormone agonists (GnRHa) given as an injection or a slow release implant for induced spawning is becoming more widely used. The addition of dopamine antagonists with GnRHa may not be necessary to successfully induce spawn some species of fish. The use of GnRHa can advance the maturation of oocytes allowing such fish to be successfully induced spawned. Significant advances have been made in the development of formulated microdiets for larval fish. Such microdiets have been used successfully with young larvae reducing the need for live foods such as artemia. The quality of both live foods and formulated diets has been enriched with the use of fatty acids. Not only the quantity of n-3 HUFAs added to a diet impacts larval growth and survival but the ratios of specific n-3 HUFAs has an impact. Enrichment of live foods with amino acids can also improve larval fish growth and survival.

Meta‐analysis of the use of seaweeds and their extracts as immunostimulants for fish: a systematic review

“…Although the concept of trained immunity exists, that is the promotion of the immune status of the progeny via the diet of the parents, and has been shown to occur in fish (Zhang et al 2019; Petit et al 2019), to our knowledge there are no reports of trained immunity achieved through use of seaweed or their extracts. The dietary supplementation of fish larvae with seaweed or its extracts could therefore be evaluated for marine fish hatcheries, which tend to have poor survival rates as larvae depend on live feed (Phelps 2010), undergo complex and metabolically demanding transformations (e.g. metamorphosis; Thépot et al 2016) and do not possess a mature immune system (Vadstein et al 2013).…”

Use, Production and Existence of Local Artemia Resources in Uganda and Africa: A Review

“…Artemia is reported to be among the most widely used live feed for larviculture of fish and shell fish (Sorgeloos, Lavens et al 1991;Philips 2010), with over 2000 metric tons of dry Artemia cysts produced and marketed annually world-wide (FAO 1996;Triantaphyllidis, Abatzopoulos et al 1996;Ogello, Kembenya et al 2014). Despite man having known Artemia for centuries, its use as food for larvae in the aquaculture industry began only in the 1930s when it was discovered to be nutritional rich for new hatched larvae FAO 1996;Ogello, Kembenya et al 2014).…”

Effect of Photoperiod on Eggs Hatchability, Growth and Survivability of Hybrid Catfish (Heterobranchus bidorsalis x. Clarias gariepinus) Larvae

“…Farmers have found this approach to be cheap, practical and highly reliable than the wild source [4]. Adequate qualitative and quantitative sexual gametes are prerequisites for a successful artificial propagation exercise, hence the need to use sexually matured and healthy breeders [5]. Parent fish must also be kept in suitable environmental conditions with good feeding to ensure quality gametes.…”